This invention relates to a cylinder head for a water-cooled internal combustion engine. The cylinder head is divided into an upper cylinder head portion receiving the valve operating assembly and a lower cylinder head portion in which the intake and exhaust ports are formed. The parting plane between the two head portions extends generally horizontally and intersects coolant chambers, whereby the head portions are manufactured such that the coolant chambers formed therein are open at the bounding faces which, in the installed state, lie in the parting plane. One of the head portions is provided with a circumferential seating face for a cylinder head cover (rocker cover) which conceals the valve operating assembly. The lower head portion has walls which have lower engagement faces tightenable against the cylinder block and which bound liquid chambers. Further, these walls extend exclusively from the intake and exhaust ports.
A horizontally divided cylinder head of the above type is known and is disclosed, for example, in German Gebrauchsmuster (utility model patent) No. 1,894,505 wherein the parting plane passes through the coolant chambers. Such an arrangement has manufacturing advantages, for example, for a die casting process and makes the use of molds and cores particularly simple.
In the known cylinder head disclosed in the above patent the upper head portion carries the usual cylinder head cover on an upwardly projecting collar, while the lower head portion has one downwardly extending wall on one side and two downwardly extending walls on the other side. These three walls are adapted to engage corresponding counter walls of the cylinder block and bound the coolant chambers or channels.
For reducing the operational noise emanating from the combustion chambers and from the valve operating assembly, it is known to surround the internal combustion engine with a capsule which usually is formed of plurality of separate wall portions. In such an encapsulated engine it is known, as disclosed, for example, in Austrian Pat. No. 350,855, to insert sound insulating intermediate components into the intake and exhaust ports in order to reduce the sound emission also from the intake and exhaust ports which pass through the capsule without contacting the same. A capsule of such a type, however, requires a substantial structural space which is only rarely available under the hood of automotive vehicles.